In my project I've been using galvo scanners for rotating small mirrors but they seem like an overkill at this point for several reasons:

1) Even though I use the slowest and smallest scanners out there, they are still over 100 grams each, in a device where every gram matters,

on top of that, their drivers are rather large (8cm x 6cm) and need special dual rail +-12V power supplies and +-5V DAC circuits to run. These all require space of their own and I need everything take up as much little space as possible.

2) While they can achieve the rotation speeds I need they seem to exceed it. The cons of using galvos which is space for all the electronics seems to outweight the pro of the high speeds which aren't used to the fullest anyway.

Since steppers just need one 3.3, 5 or 12V PSU and one stepper driver I thought I'd give them a try.

The smallest steppers I am aware of which are readily available are NEMA 14, which is huge for this.

The requirements are simple:

1) torque is extremely low as a small 10x10mm 1mm thick mirror is rotated which is glued onto it.

2) acceleration and rotation speeds are important and demanding though: 500 degree/second

I've found a stepper but the rotation speed is abysmal for this. The 28BYJ-48

My question is this:

1) Can small enough steppers meet this criteria (low torque but high speed requirement) at all? Bigger motors seem to achieve the desired result https://youtu.be/KgPyR0Rg3FQ?t=1m17s 2) If yes, what stepper(s) should I check. 3) can they not make those loud sqeaky noises like in CNCs and 3d printers?


  • $\begingroup$ This vendor has some NEMA 8 options, do those work? omc-stepperonline.com/nema-8-stepper-motor $\endgroup$
    – ericksonla
    Jun 6, 2018 at 18:04
  • $\begingroup$ Micromo has steppers as small as 6mm in diameter: micromo.com/products/stepper-motors/stepper-motors-datasheets $\endgroup$
    – Eric S
    Sep 4, 2018 at 19:25
  • $\begingroup$ Consider rolling your own galvo. A tiny magnet with the mirror on a needle suspending it in a bracket of sheet metal (with dimples punched into the sides to hold the needle), a pair of electromagnets (could be earphone coils) and some circuitry to power them up. $\endgroup$
    – SF.
    Sep 5, 2018 at 9:02

1 Answer 1


This is a good question you could modify 12volt a 3-5 watt brush less water pump commonly found on ebay from China to run a gear instead of impellers . You can add a dimmer switch to control the revolutions. You may have to change out the motor more often but for 3 dollars each. These motors run fine dry and is about 2-4 inches cubed.

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Remove the screws to expose the drive shaft and impellers.


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